On the front edge of the Nintendo DS between the headphone jack plug and volume controls remove the plastic insert (or cartridge) from the lower slot (Slot 2).
Flip the unit over so that it is facing right-side up.
Use a spudger to pry open the gap between the bottom case and the front panel. Work all the way around the case until the panel is free.
Avoid touching the L and R shoulder buttons, because they easily detach and are difficult to reassemble. Keep the bottom case flat against your workbench to help hold the shoulder buttons in place.
The two shoulder buttons are made up of three pieces -- the plastic button, a pin, and a spring. If they accidentally pop out while you are working, study the picture and make sure you put the spring in the correct position.
When reassembling the cover, make sure that the power switch caver on the bottom case is in the off (down) position to avoid breakage.
Using one finger nail or the plastic opening tool, carefully lift the brown securing flap of the connector. Then disconnect the ribbon cable that connects the logic board to the upper screen.
The speakers are soldered to the top screen flex assembly. You may desolder a broken speaker and solder a working speaker on, or you may replace the speakers together with the display assembly.